<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>
		<script type="text/javascript">
			//一个盒子里有20个鸡蛋 当用户输入鸡蛋数，求需要多少个盒子
  			// let eggs = prompt("请输入鸡蛋数量：");
  			// let boxes = parseInt(eggs / 20);
  			// let c = eggs % 20 > 0 ;
  			// console.log('需要的盒子数量是：' + (boxes + c));
  			// const eggs = parseInt(prompt("请输入鸡蛋数量："));
			// const boxes = Math.ceil(eggs / 20);
			// MaTh.ceil有小数点会向上取值
			// alert(`需要的盒子数量是：${boxes}`);
			// ${boxes}会接收const boxes = Math.ceil(eggs / 20);的值


			// 假设今天周四，1000天之后，周几
			// console.log("1000天后是："+"周"+((1000 % 7) + 4 - 7))
			// let now = 1000 % 7 -3
			// console.log(now)
		</script>
		<script type="text/javascript">
		// var a = 1 + undefined; //NaN
		// var a1 = '' + null;//null
		// var a2 = null + true * '4'//4
		// var a3 = '' + undefined //undefined
		// var a4 = "4" + "0" -5 +15//50
		// var a5 ="4" / "2" * (2 + "1")//42 
		// var a6 = "4" + true * "4";//"44" 
		// var a7 = '4Q' + '4' + 2;//"4q42"
		// var a8 = '4K' + '4' + null//"4k4null"
		// var a9 = '4月' - '月' + 2;//NaN
		// var a10 = parseInt('10' + '01' * '20' + "4K") //10204
		// var a11 = parseInt(Number('3.14Π') * false + '10' * 2 + '4k') //NaN

		// var a12 = Number(parseFloat('3.14Π') - '0.14' * true) //3
		// var a13 = ' ' + null + 0 + undefined + true + false//null0undefinedtruefalse
		// var a14 = '10' - 5 > '0.3' * '1.5'//true
		// var a15 = ((!undefined) == !' ' - true) + '10'//false10
		// var a16 = parseInt(10.2 * '100' + '4K')//1019
		// var a17 = 0 + null + undefined + false + true + ''//NaN
			var a = -4 +"3"+10-"-5"*2
			console.log(a)
		
		 
	</script>
</body>
</html>